Drug-induced thrombocytopenia: clinical data on 309 cases and the effect of corticosteroid therapy

Objective: To analyse the clinical picture and the course of thrombocytopenia induced by non-cytotoxic drugs, and to evaluate a possible therapeutic effect of corticosteroids. Methods: A retrospective analysis of 309 well-documented cases of drug-induced thrombocytopenia was performed. Data sources were reports from the files of the Danish Committee on Adverse Drug Reactions and discharge summaries. Results: The median length of exposure to the offending drug, before development of thrombocytopenia, was 21 days. The median nadir platelet count was 11 × 10⁹ · l⁻¹, and 74% of the patients had clinical haemorrhage. Bone marrow examination generally showed hyperplastic reactive changes and a variable number of megakaryocytes. Slight leucopenia was present in 6% of the patients and 16% were anaemic. Complete recovery was seen in 87% of cases, with a median recovery rate of 8 days. The standard treatment was corticosteroids, which were administered in 53% of the cases. No difference in recovery between corticosteroid-treated and untreated patients was observed. No other clinical parameter affected the recovery rate. The mortality rate due to haemorrhage was 3.6%. Conclusion: Thrombocytopenia induced by non-cytotoxic drugs is characterised by a heterogeneous clinical picture and recovery is generally rapid. Although corticosteroids seem inefficient, we still recommend that severe symptomatic cases of drug-induced thrombocytopenia are treated as idiopathic thrombocytopenic purpura due to the difficult initial differentiation between the two conditions. Received: 11 October 1996 / Accepted in revised form: 24 December 1996